glibc/inet/rcmd.c

490 lines
12 KiB
C

/*
* Copyright (c) 1983, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94";
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <alloca.h>
#include <signal.h>
#include <fcntl.h>
#include <netdb.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
int __ivaliduser __P((FILE *, u_int32_t, const char *, const char *));
static int __icheckhost __P((u_int32_t, char *)) internal_function;
int
rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
char **ahost;
u_short rport;
const char *locuser, *remuser, *cmd;
int *fd2p;
{
struct hostent hostbuf, *hp;
size_t hstbuflen;
char *tmphstbuf;
struct sockaddr_in sin, from;
struct pollfd pfd[2];
int32_t oldmask;
pid_t pid;
int s, lport, timo;
char c;
int herr;
pid = getpid();
hstbuflen = 1024;
tmphstbuf = __alloca (hstbuflen);
while (__gethostbyname_r (*ahost, &hostbuf, tmphstbuf, hstbuflen,
&hp, &herr) < 0)
if (herr != NETDB_INTERNAL || errno != ERANGE)
{
__set_h_errno (herr);
herror(*ahost);
return -1;
}
else
{
/* Enlarge the buffer. */
hstbuflen *= 2;
tmphstbuf = __alloca (hstbuflen);
}
pfd[0].events = POLLIN;
pfd[1].events = POLLIN;
*ahost = hp->h_name;
oldmask = sigblock(sigmask(SIGURG));
for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
s = rresvport(&lport);
if (s < 0) {
if (errno == EAGAIN)
(void)fprintf(stderr,
_("rcmd: socket: All ports in use\n"));
else
(void)fprintf(stderr, "rcmd: socket: %m\n");
sigsetmask(oldmask);
return -1;
}
fcntl(s, F_SETOWN, pid);
sin.sin_family = hp->h_addrtype;
bcopy(hp->h_addr_list[0], &sin.sin_addr,
MIN (sizeof (sin.sin_addr), hp->h_length));
sin.sin_port = rport;
if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
break;
(void)close(s);
if (errno == EADDRINUSE) {
lport--;
continue;
}
if (errno == ECONNREFUSED && timo <= 16) {
(void)sleep(timo);
timo *= 2;
continue;
}
if (hp->h_addr_list[1] != NULL) {
int oerrno = errno;
(void)fprintf(stderr, _("connect to address %s: "),
inet_ntoa(sin.sin_addr));
__set_errno (oerrno);
perror(0);
hp->h_addr_list++;
bcopy(hp->h_addr_list[0], &sin.sin_addr,
MIN (sizeof (sin.sin_addr), hp->h_length));
(void)fprintf(stderr, _("Trying %s...\n"),
inet_ntoa(sin.sin_addr));
continue;
}
(void)fprintf(stderr, "%s: %m\n", hp->h_name);
sigsetmask(oldmask);
return -1;
}
lport--;
if (fd2p == 0) {
write(s, "", 1);
lport = 0;
} else {
char num[8];
int s2 = rresvport(&lport), s3;
size_t len = sizeof(from);
if (s2 < 0)
goto bad;
listen(s2, 1);
(void)snprintf(num, sizeof(num), "%d", lport);
if (write(s, num, strlen(num)+1) != strlen(num)+1) {
(void)fprintf(stderr,
_("rcmd: write (setting up stderr): %m\n"));
(void)close(s2);
goto bad;
}
pfd[0].fd = s;
pfd[1].fd = s2;
__set_errno (0);
if (__poll (pfd, 2, -1) < 1 || (pfd[1].revents & POLLIN) == 0){
if (errno != 0)
(void)fprintf(stderr,
_("rcmd: poll (setting up stderr): %m\n"));
else
(void)fprintf(stderr,
_("poll: protocol failure in circuit setup\n"));
(void)close(s2);
goto bad;
}
s3 = accept(s2, (struct sockaddr *)&from, &len);
(void)close(s2);
if (s3 < 0) {
(void)fprintf(stderr,
"rcmd: accept: %m\n");
lport = 0;
goto bad;
}
*fd2p = s3;
from.sin_port = ntohs((u_short)from.sin_port);
if (from.sin_family != AF_INET ||
from.sin_port >= IPPORT_RESERVED ||
from.sin_port < IPPORT_RESERVED / 2) {
(void)fprintf(stderr,
_("socket: protocol failure in circuit setup\n"));
goto bad2;
}
}
(void)write(s, locuser, strlen(locuser)+1);
(void)write(s, remuser, strlen(remuser)+1);
(void)write(s, cmd, strlen(cmd)+1);
if (read(s, &c, 1) != 1) {
(void)fprintf(stderr,
"rcmd: %s: %m\n", *ahost);
goto bad2;
}
if (c != 0) {
while (read(s, &c, 1) == 1) {
(void)write(STDERR_FILENO, &c, 1);
if (c == '\n')
break;
}
goto bad2;
}
sigsetmask(oldmask);
return s;
bad2:
if (lport)
(void)close(*fd2p);
bad:
(void)close(s);
sigsetmask(oldmask);
return -1;
}
int
rresvport(alport)
int *alport;
{
struct sockaddr_in sin;
int s;
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
s = socket(AF_INET, SOCK_STREAM, 0);
if (s < 0)
return -1;
for (;;) {
sin.sin_port = htons((u_short)*alport);
if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
return s;
if (errno != EADDRINUSE) {
(void)close(s);
return -1;
}
(*alport)--;
if (*alport == IPPORT_RESERVED/2) {
(void)close(s);
__set_errno (EAGAIN); /* close */
return -1;
}
}
}
int __check_rhosts_file = 1;
char *__rcmd_errstr;
int
ruserok(rhost, superuser, ruser, luser)
const char *rhost, *ruser, *luser;
int superuser;
{
struct hostent hostbuf, *hp;
size_t buflen;
char *buffer;
u_int32_t addr;
char **ap;
int herr;
buflen = 1024;
buffer = __alloca (buflen);
while (__gethostbyname_r (rhost, &hostbuf, buffer, buflen, &hp, &herr)
< 0)
if (herr != NETDB_INTERNAL || errno != ERANGE)
return -1;
else
{
/* Enlarge the buffer. */
buflen *= 2;
buffer = __alloca (buflen);
}
for (ap = hp->h_addr_list; *ap; ++ap) {
bcopy(*ap, &addr, sizeof(addr));
if (iruserok(addr, superuser, ruser, luser) == 0)
return 0;
}
return -1;
}
/* Extremely paranoid file open function. */
static FILE *
iruserfopen (char *file, uid_t okuser)
{
struct stat st;
char *cp = NULL;
FILE *res = NULL;
/* If not a regular file, if owned by someone other than user or
root, if writeable by anyone but the owner, or if hardlinked
anywhere, quit. */
cp = NULL;
if (__lxstat (_STAT_VER, file, &st))
cp = _("lstat failed");
else if (!S_ISREG (st.st_mode))
cp = _("not regular file");
else
{
res = fopen (file, "r");
if (!res)
cp = _("cannot open");
else if (__fxstat (_STAT_VER, fileno (res), &st) < 0)
cp = _("fstat failed");
else if (st.st_uid && st.st_uid != okuser)
cp = _("bad owner");
else if (st.st_mode & (S_IWGRP|S_IWOTH))
cp = _("writeable by other than owner");
else if (st.st_nlink > 1)
cp = _("hard linked somewhere");
}
/* If there were any problems, quit. */
if (cp != NULL)
{
__rcmd_errstr = cp;
if (res)
fclose (res);
return NULL;
}
return res;
}
/*
* New .rhosts strategy: We are passed an ip address. We spin through
* hosts.equiv and .rhosts looking for a match. When the .rhosts only
* has ip addresses, we don't have to trust a nameserver. When it
* contains hostnames, we spin through the list of addresses the nameserver
* gives us and look for a match.
*
* Returns 0 if ok, -1 if not ok.
*/
int
iruserok (raddr, superuser, ruser, luser)
u_int32_t raddr;
int superuser;
const char *ruser, *luser;
{
FILE *hostf = NULL;
int isbad;
if (!superuser)
hostf = iruserfopen (_PATH_HEQUIV, 0);
if (hostf)
{
isbad = __ivaliduser (hostf, raddr, luser, ruser);
fclose (hostf);
if (!isbad)
return 0;
}
if (__check_rhosts_file || superuser)
{
char *pbuf;
struct passwd pwdbuf, *pwd;
size_t dirlen;
size_t buflen = __sysconf (_SC_GETPW_R_SIZE_MAX);
char *buffer = __alloca (buflen);
uid_t uid;
if (__getpwnam_r (luser, &pwdbuf, buffer, buflen, &pwd))
return -1;
dirlen = strlen (pwd->pw_dir);
pbuf = alloca (dirlen + sizeof "/.rhosts");
__mempcpy (__mempcpy (pbuf, pwd->pw_dir, dirlen),
"/.rhosts", sizeof "/.rhosts");
/* Change effective uid while reading .rhosts. If root and
reading an NFS mounted file system, can't read files that
are protected read/write owner only. */
uid = geteuid ();
seteuid (pwd->pw_uid);
hostf = iruserfopen (pbuf, pwd->pw_uid);
if (hostf != NULL)
{
isbad = __ivaliduser (hostf, raddr, luser, ruser);
fclose (hostf);
}
seteuid (uid);
return isbad;
}
return -1;
}
/*
* XXX
* Don't make static, used by lpd(8).
*
* Returns 0 if ok, -1 if not ok.
*/
int
__ivaliduser(hostf, raddr, luser, ruser)
FILE *hostf;
u_int32_t raddr;
const char *luser, *ruser;
{
register char *user, *p;
int ch;
char *buf = NULL;
size_t bufsize = 0;
ssize_t nread;
while ((nread = __getline (&buf, &bufsize, hostf)) > 0) {
buf[bufsize - 1] = '\0'; /* Make sure it's terminated. */
p = buf;
while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
*p = isupper(*p) ? tolower(*p) : *p;
p++;
}
if (*p == ' ' || *p == '\t') {
*p++ = '\0';
while (*p == ' ' || *p == '\t')
p++;
user = p;
while (*p != '\n' && *p != ' ' &&
*p != '\t' && *p != '\0')
p++;
} else
user = p;
*p = '\0';
if (__icheckhost(raddr, buf) &&
strcmp(ruser, *user ? user : luser) == 0) {
free (buf);
return 0;
}
}
if (buf != NULL)
free (buf);
return -1;
}
/*
* Returns "true" if match, 0 if no match.
*/
static int
internal_function
__icheckhost(raddr, lhost)
u_int32_t raddr;
register char *lhost;
{
struct hostent hostbuf, *hp;
size_t buflen;
char *buffer;
register u_int32_t laddr;
register char **pp;
int herr;
/* Try for raw ip address first. */
if (isdigit(*lhost) && (int32_t)(laddr = inet_addr(lhost)) != -1)
return raddr == laddr;
/* Better be a hostname. */
buflen = 1024;
buffer = __alloca (buflen);
while (__gethostbyname_r (lhost, &hostbuf, buffer, buflen, &hp, &herr)
< 0)
if (herr != NETDB_INTERNAL || errno != ERANGE)
return 0;
else
{
/* Enlarge the buffer. */
buflen *= 2;
buffer = __alloca (buflen);
}
/* Spin through ip addresses. */
for (pp = hp->h_addr_list; *pp; ++pp)
if (!bcmp(&raddr, *pp, sizeof(u_int32_t)))
return 1;
/* No match. */
return 0;
}